[Josy]

A powerful earthquake has hit north-east Japan, exactly one month after the devastating earthquake and tsunami.

The 7.1-magnitude tremor triggered a brief tsunami warning, and forced workers to evacuate the crippled Fukushima nuclear plant.

The epicentre of the quake was in Fukushima prefecture, and struck at a depth of just 10km (six miles).

It came as Japan said it was extending the evacuation zone around the nuclear plant because of radiation concerns.

The cooling systems at the Fukushima Daiichi nuclear plant were damaged in last month's disaster. Workers have been struggling to prevent several reactors from overheating, and avert a large-scale release of radiation.

The plant's operator, Tepco, said power used to pump water to cool three damaged reactors had been cut briefly but early indications suggested the plant had not sustained any further damage.

The zone around it will be widened to encompass five communities beyond the existing 20-km (12-mile) radius, following new data about accumulated radiation levels, officials said.

Top government spokesman Yukio Edano said the new evacuations would take place over the coming month, from areas including Iitate village, which lies 40km from the power station, and part of the city of Kawamata.

"There is no need to evacuate immediately," he told a news conference, but added that there were concerns about long-term health risks.


http://www.bbc.co.uk/news/world-asia-pacific-13032122